Der Tunnel (2017)

On his weekly train ride through Switzerland a student notices that the tunnel they are driving through is unusually long. The persistent darkness makes him increasingly apprehensive. His fellow passengers don't seem concerned. Even the conductor reassures him that everything is fine. But when he heads to the engineer's cabin with the chief conductor - they find it empty. And after their effort to pull the emergency break fails, they watch the rapidly accelerating train head straight into a dark abyss.